1/* rename.c -- rename a file, preserving symlinks.
2   Copyright 1999, 2002, 2003 Free Software Foundation, Inc.
3
4   This file is part of GNU Binutils.
5
6   This program is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 2 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program; if not, write to the Free Software
18   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
19   02110-1301, USA.  */
20
21#include "bfd.h"
22#include "bucomm.h"
23
24#include <sys/stat.h>
25
26#ifdef HAVE_GOOD_UTIME_H
27#include <utime.h>
28#else /* ! HAVE_GOOD_UTIME_H */
29#ifdef HAVE_UTIMES
30#include <sys/time.h>
31#endif /* HAVE_UTIMES */
32#endif /* ! HAVE_GOOD_UTIME_H */
33
34/* We need to open the file in binary modes on system where that makes
35   a difference.  */
36#ifndef O_BINARY
37#define O_BINARY 0
38#endif
39
40#if ! defined (_WIN32) || defined (__CYGWIN32__)
41static int simple_copy (const char *, const char *);
42
43/* The number of bytes to copy at once.  */
44#define COPY_BUF 8192
45
46/* Copy file FROM to file TO, performing no translations.
47   Return 0 if ok, -1 if error.  */
48
49static int
50simple_copy (const char *from, const char *to)
51{
52  int fromfd, tofd, nread;
53  int saved;
54  char buf[COPY_BUF];
55
56  fromfd = open (from, O_RDONLY | O_BINARY);
57  if (fromfd < 0)
58    return -1;
59#ifdef O_CREAT
60  tofd = open (to, O_CREAT | O_WRONLY | O_TRUNC | O_BINARY, 0777);
61#else
62  tofd = creat (to, 0777);
63#endif
64  if (tofd < 0)
65    {
66      saved = errno;
67      close (fromfd);
68      errno = saved;
69      return -1;
70    }
71  while ((nread = read (fromfd, buf, sizeof buf)) > 0)
72    {
73      if (write (tofd, buf, nread) != nread)
74	{
75	  saved = errno;
76	  close (fromfd);
77	  close (tofd);
78	  errno = saved;
79	  return -1;
80	}
81    }
82  saved = errno;
83  close (fromfd);
84  close (tofd);
85  if (nread < 0)
86    {
87      errno = saved;
88      return -1;
89    }
90  return 0;
91}
92#endif /* __CYGWIN32__ or not _WIN32 */
93
94/* Set the times of the file DESTINATION to be the same as those in
95   STATBUF.  */
96
97void
98set_times (const char *destination, const struct stat *statbuf)
99{
100  int result;
101
102  {
103#ifdef HAVE_GOOD_UTIME_H
104    struct utimbuf tb;
105
106    tb.actime = statbuf->st_atime;
107    tb.modtime = statbuf->st_mtime;
108    result = utime (destination, &tb);
109#else /* ! HAVE_GOOD_UTIME_H */
110#ifndef HAVE_UTIMES
111    long tb[2];
112
113    tb[0] = statbuf->st_atime;
114    tb[1] = statbuf->st_mtime;
115    result = utime (destination, tb);
116#else /* HAVE_UTIMES */
117    struct timeval tv[2];
118
119    tv[0].tv_sec = statbuf->st_atime;
120    tv[0].tv_usec = 0;
121    tv[1].tv_sec = statbuf->st_mtime;
122    tv[1].tv_usec = 0;
123    result = utimes (destination, tv);
124#endif /* HAVE_UTIMES */
125#endif /* ! HAVE_GOOD_UTIME_H */
126  }
127
128  if (result != 0)
129    non_fatal (_("%s: cannot set time: %s"), destination, strerror (errno));
130}
131
132#ifndef S_ISLNK
133#ifdef S_IFLNK
134#define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
135#else
136#define S_ISLNK(m) 0
137#define lstat stat
138#endif
139#endif
140
141/* Rename FROM to TO, copying if TO is a link.
142   Return 0 if ok, -1 if error.  */
143
144int
145smart_rename (const char *from, const char *to, int preserve_dates ATTRIBUTE_UNUSED)
146{
147  bfd_boolean exists;
148  struct stat s;
149  int ret = 0;
150
151  exists = lstat (to, &s) == 0;
152
153#if defined (_WIN32) && !defined (__CYGWIN32__)
154  /* Win32, unlike unix, will not erase `to' in `rename(from, to)' but
155     fail instead.  Also, chown is not present.  */
156
157  if (exists)
158    remove (to);
159
160  ret = rename (from, to);
161  if (ret != 0)
162    {
163      /* We have to clean up here.  */
164      non_fatal (_("unable to rename '%s' reason: %s"), to, strerror (errno));
165      unlink (from);
166    }
167#else
168  /* Use rename only if TO is not a symbolic link and has
169     only one hard link, and we have permission to write to it.  */
170  if (! exists
171      || (!S_ISLNK (s.st_mode)
172	  && S_ISREG (s.st_mode)
173	  && (s.st_mode & S_IWUSR)
174	  && s.st_nlink == 1)
175      )
176    {
177      ret = rename (from, to);
178      if (ret == 0)
179	{
180	  if (exists)
181	    {
182	      /* Try to preserve the permission bits and ownership of
183		 TO.  First get the mode right except for the setuid
184		 bit.  Then change the ownership.  Then fix the setuid
185		 bit.  We do the chmod before the chown because if the
186		 chown succeeds, and we are a normal user, we won't be
187		 able to do the chmod afterward.  We don't bother to
188		 fix the setuid bit first because that might introduce
189		 a fleeting security problem, and because the chown
190		 will clear the setuid bit anyhow.  We only fix the
191		 setuid bit if the chown succeeds, because we don't
192		 want to introduce an unexpected setuid file owned by
193		 the user running objcopy.  */
194	      chmod (to, s.st_mode & 0777);
195	      if (chown (to, s.st_uid, s.st_gid) >= 0)
196		chmod (to, s.st_mode & 07777);
197	    }
198	}
199      else
200	{
201	  /* We have to clean up here.  */
202	  non_fatal (_("unable to rename '%s' reason: %s"), to, strerror (errno));
203	  unlink (from);
204	}
205    }
206  else
207    {
208      ret = simple_copy (from, to);
209      if (ret != 0)
210	non_fatal (_("unable to copy file '%s' reason: %s"), to, strerror (errno));
211
212      if (preserve_dates)
213	set_times (to, &s);
214      unlink (from);
215    }
216#endif /* _WIN32 && !__CYGWIN32__ */
217
218  return ret;
219}
220